General Description

2-Anilino-6-dibutylamino-3-methylfluoran is a fluorochrome compound known for its reversible color change under UV light, making it ideal for security inks and anti-counterfeiting labels. Its unique structure enables precise optical properties crucial for applications in light-driven phase change materials systems. By incorporating this compound into thermochromic phase change materials, stable equilibrium temperatures are achieved, enhancing temperature control efficiency. The preparation method involves specific reactions and conditions to yield the desired product efficiently. In summary, 2-Anilino-6-dibutylamino-3-methylfluoran offers versatile functionality in optical and security applications, showcasing its significance in industries requiring reliability and precision.

Figure 1. 2-Anilino-6-dibutylamino-3-methylfluoran

Overview

2-Anilino-6-dibutylamino-3-methylfluoran is a fluorochrome compound known for its distinctive optical properties. When exposed to UV light, it undergoes a reversible color change from colorless to a vivid blue or purple hue, reverting back to its original colorless state once removed from UV radiation. This unique characteristic renders it highly suitable for a range of applications including pressure-sensitive copying systems, anti-counterfeiting labels, and security inks. The compound's stability and remarkable sensitivity to UV light are key factors driving its extensive utilization in these fields. The specific arrangement of chemical groups - the anilino group at the 2-position, the dibutylamino group at the 6-position, and the methyl substituent at the 3-position - play pivotal roles in determining its distinct photochemical behavior. These structural elements contribute to its effectiveness as a crucial component in various optical and security applications, emphasizing its significance in industries requiring precision and reliability. In summary, 2-Anilino-6-dibutylamino-3-methylfluoran stands out as a valuable fluorochrome compound offering versatile functionality and reliability in diverse applications where optical responsiveness and security are paramount. ¹

Applications in Light-Driven Phase Change Materials System

2-Anilino-6-dibutylamino-3-methylfluoran plays a crucial role in the development of temperature-controlled light-driven phase change materials (PCMs) systems. These PCMs have garnered attention for their ability to convert visible light into thermal energy and store it as latent heat. However, the continuous conversion of light into heat can lead to high equilibrium temperatures post-phase transition. To address this issue, a novel PCM system was devised by incorporating a thermochromic compound like 2-Anilino-6-dibutylamino-3-methylfluoran. In this study, thermochromic phase change materials (TC-PCMs) were formulated by blending 2-Anilino-6-dibutylamino-3-methylfluoran and bisphenol A with 1-hexadecanol (1-HD) in different ratios. The performance of these TC-PCMs was evaluated under solar radiation and xenon lamp irradiation. Notably, the TC-PCMs exhibited a unique temperature-control mechanism, leading to lower equilibrium temperatures due to varying absorbance properties. For instance, TC-PCM180 (with an ODB-2:BPA:1-HD ratio of 1:2:180) demonstrated stable equilibrium at around 54°C. Moreover, these TC-PCMs displayed excellent reversibility and repeatability over multiple irradiation and cooling cycles, making them promising candidates for applications requiring precise temperature control in light-driven PCM systems. The incorporation of 2-Anilino-6-dibutylamino-3-methylfluoran enhances the overall performance and efficiency of the PCM system, showcasing its potential for various practical applications in temperature-sensitive environments. ²

Preparation Method

The preparation method for 2-Anilino-6-dibutylamino-3-methylfluoran involves several key steps. Firstly, N-formyl-4-methoxy-2-Me diphenylamine and N,N-dibutyl-2-hydroxy ketone acid are reacted in the presence of concentrated sulfuric acid at a temperature range of 15-25°C for 4-48 hours. This reaction results in the formation of a compound, which is then solidified by adding cool water and filtered. Next, a base (such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, ammonia, or sodium sulfide) and water are added to the filtered compound along with an organic solvent. The base is neutralized until the pH reaches or exceeds 11. The mixture is refluxed for 4-6 hours, followed by cooling, filtering, and washing to obtain the title compound, 2-Anilino-6-dibutylamino-3-methylfluoran. Overall, this method yields the desired product with an efficiency of 83%. It is essential to maintain specific reaction conditions and adhere to precise steps to ensure the successful synthesis of this thermal sensitive dye. By following these outlined procedures meticulously, one can effectively prepare 2-Anilino-6-dibutylamino-3-methylfluoran for various applications requiring a thermal sensitive dye. ³

Reference

1. 2-Anilino-3-methyl-6-(dibutylamino)fluoran. National Center for Biotechnology Information. 2024; PubChem Compound Summary for CID 3534526.

2. Ren C, Liu F, Umair MM, Jin X, Zhang S, Tang B. Excellent Temperature-Control Based on Reversible Thermochromic Materials for Light-Driven Phase Change Materials System. Molecules. 2019; 24(8): 1623.

3. Yang, WG, Song WG, Fang YX, Yang CC. Method for preparation of thermal sensitive dye of 3-dibutyl-amino-6-methyl-7-aniline fluorane. 2006; Patent Number: CN1854201.